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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2001-1-23
pubmed:databankReference
pubmed:abstractText
Chlorosomes of the green sulfur bacterium Chlorobium tepidum have previously been shown to contain at least 10 polypeptides [Chung, S., Frank, G., Zuber, H., and Bryant, D. A. (1994) Photosynth. Res. 41, 261-275]. Based upon the N-terminal amino acid sequences determined for two of these proteins, the corresponding genes were isolated using degenerate oligonucleotide hybridization probes. The csmI and csmJ genes encode proteins of 244 and 225 amino acids, respectively. A third gene, denoted csmX, that predicts a protein of 221 amino acids with strong sequence similarity to CsmI and CsmJ, was found to be encoded immediately upstream from the csmJ gene. All three proteins have strong sequence similarity in their amino-terminal domains to [2Fe-2S] ferredoxins of the adrenodoxin/putidaredoxin subfamily of ferredoxins. CsmI and CsmJ were overproduced in Escherichia coli, and both proteins were shown by EPR spectroscopy to contain iron-sulfur clusters. The g-tensor and relaxation properties are consistent with their assignment as [2Fe-2S] clusters. Isolated chlorosomes were also shown to contain [2Fe-2S] clusters whose properties were similar to those of the recombinant CsmI and CsmJ proteins. Redox titration of isolated chlorosomes showed these clusters to have potentials of about -201 and +92 mV vs SHE. The former potential is similar to that measured by redox titration of the clusters in inclusion bodies of CsmJ. Possible roles for these iron-sulfur proteins in electron transport and light harvesting are discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
464-73
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:11148041-Amino Acid Sequence, pubmed-meshheading:11148041-Bacterial Proteins, pubmed-meshheading:11148041-Chlorobi, pubmed-meshheading:11148041-Cloning, Molecular, pubmed-meshheading:11148041-Electron Spin Resonance Spectroscopy, pubmed-meshheading:11148041-Electron Transport, pubmed-meshheading:11148041-Escherichia coli, pubmed-meshheading:11148041-Ferredoxins, pubmed-meshheading:11148041-Genes, Bacterial, pubmed-meshheading:11148041-Intracellular Membranes, pubmed-meshheading:11148041-Iron-Sulfur Proteins, pubmed-meshheading:11148041-Molecular Sequence Data, pubmed-meshheading:11148041-Oxidation-Reduction, pubmed-meshheading:11148041-Plasmids, pubmed-meshheading:11148041-Recombinant Proteins, pubmed-meshheading:11148041-Sequence Analysis, Protein, pubmed-meshheading:11148041-Sequence Homology, Amino Acid
pubmed:year
2001
pubmed:articleTitle
Electron transfer may occur in the chlorosome envelope: the CsmI and CsmJ proteins of chlorosomes are 2Fe-2S ferredoxins.
pubmed:affiliation
Department of Biochemistry and Molecular Biology and Center for Biomolecular Structure and Function, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.